WASHINGTON — The U.S. military’s Pacific Command said on Saturday there was no threat to Hawaii after an official message was erroneously sent to Hawaii residents’ mobile phones warning them of an imminent ballistic missile attack.

The U.S. Federal Communications Commission announced that it was initiating a full investigation of the incident.

The erroneous alert came from the Hawaii Emergency Management Agency. CNN reported that Governor David Ige said it was sent when an employee pushed the wrong button during a shift change.

The agency later said on Twitter: “NO missile threat to Hawaii.”

A spokesman for the Pacific Command also said it ”detected no ballistic missile threat to Hawaii and that the message warning had been sent in error.

The false alarm was issued amid high international tensions over North Korea’s development of a ballistic nuclear weapon.

North Korean President Kim Jong-un has threatened to unleash his country’s growing missile weapon capability against the U.S. territory of Guam or U.S. states, prompting President Donald Trump to threaten tough actions against Pyongyang, including “fire and fury.”

Trump was wrapping up a round of golf at Trump International Golf Club in West Palm Beach, Florida, when the problem was unfolding. White House spokeswoman Lindsay Walters said he was briefed and that it “was purely a state exercise.”

A spokeswoman for U.S. Representative Tulsi Gabbard said she checked with the state agency that issued the alert and was told it was sent in error.

Gabbard then tweeted, “HAWAII — THIS IS A FALSE ALARM. THERE IS NO INCOMING MISSILE TO HAWAII. I HAVE CONFIRMED WITH OFFICIALS THERE IS NO INCOMING MISSILE.”

Gabbard also tweeted the mistaken alert, which stated: “EMERGENCY ALERT BALLISTIC MISSILE THREAT INBOUND TO HAWAII. SEEK IMMEDIATE SHELTER. THIS IS NOT A DRILL.”

In an interview on CNN, an angry Gabbard said, “I think first you’d be horrified and, second, once you realized it’s not going to happen, now the anger is going to come.”

Hawaii, a chain of islands in the Pacific Ocean, has a population of about 1.4 million people, according to the U.S. Census Bureau, and is home to the U.S. Pacific Command, the Navy’s Pacific Fleet and other elements of the American military.

The U.S. Navy base at Pearl Harbor, Hawaii, was the target of the surprise attack by Japan on Dec. 7, 1941, that drew the United States into World War Two.

In November, Hawaii said it would resume monthly statewide testing of Cold War-era nuclear attack warning sirens for the first time in at least a quarter of a century, in preparation for a possible missile strike from North Korea, state officials said at the time.

U.S. Senator Mazie Hirono, a Democrat from Hawaii, said on Twitter, “Today’s alert was a false alarm. At a time of heightened tensions, we need to make sure all information released to the community is accurate. We need to get to the bottom of what happened and make sure it never happens again.”